This study aimed to investigate the effects on nutrient intake and digestibility, milk yield (MY) and composition, milk fatty acids profile, and microbial protein synthesis caused by feeding lactating dairy cows four different forage cactus genotypes. Eight Girolando cows (5/8 Holstein × 3/8 Gyr), weighing 490 ± 69.0 kg (means ± standard deviation), and producing 15.5 ± 1.0 kg/d of milk during pretrial were distributed to two contemporaneous 4 × 4 Latin squares. The cows were fed a total mixed ration composed of sorghum silage (385 g/kg of dry matter (DM)), concentrated mix (175 g/kg DM), and forage cactus (440 g/kg DM). The experimental treatments consisted of different cactus genotypes, such as Gigante cactus (GC), Miúda cactus (MC), IPA Sertânia cactus (SC), and Orelha de Elefante Mexicana cactus (OEMC). The feeding of MC provided a higher intake of DM, organic matter (OM), and total digestible nutrients, as well as higher MY, energy-corrected milk, and microbial protein synthesis in comparison with those resulting from the other genotypes tested. The GC promoted lower DM and OM, and the apparent digestibility of neutral detergent fiber. The cows fed with OEMC showed lower MY and milk protein yield and content, and higher unsaturated over saturated fatty acid ratio in milk. Miúda forage cactus increased nutrient intake, digestibility of DM and OM, and microbial synthesis without impairing the milk fatty acid profile.

This study evaluated the effect of different roughages fed to sheep on nutrient and water intake, ingestive behavior, nitrogen balance, microbial protein synthesis, fermentation parameters, and methane production using an in vitro gas production system. The treatments consisted of five diets: cactus cladodes Nopalea (NUB) and Opuntia (OUB), both with the addition of sugarcane bagasse (SB) and urea/ammonium sulfate (urea/as); Tifton hay (TH); corn silage (CS); and sorghum silage (SS), also with added urea/as. The NUB provided greater (p ≤ 0.03) intakes of dry matter (1024 g/d), digestible organic matter (670 g/d), and crude protein (161 g/d) than those on the SS. The NUB provided greater (p < 0.01) dietary water intake (3023 g/d) than TH. The time spent on rumination was shorter (p < 0.01), and the idle time was longer in animals fed NUB and OUB than TH and CS. Microbial protein synthesis was not affected (p = 0.27). The final pH (6.4) of the incubation fluid and the concentration of NH₃-N (39.05 mg/dL) were greater for NUB and OUB. Ruminal parameters and methane production were little or not affected by tested forages. We recommend using cactus cladodes in combination with sugarcane bagasse and urea/as in sheep diets.

We aimed to evaluate the effect of the cactus cladodes Nopalea cochenillifera (L). Salm-Dyck. (NUB) and cactus cladodes Opuntia stricta (Haw.) Haw. (OUB), both combined with sugarcane bagasse (SB) plus urea, Tifton hay (TH), corn silage (CS), and sorghum silage (SS) plus urea on nutrient intake and digestibility, ruminal dynamics, and parameters. Five male sheep, fistulated in the rumen, were assigned in a 5 × 5 Latin square design. The NUB provided a higher intake of dry matter (DM) and any nutrients than SS. TH provided larger pools of DM and iNDF. The OUB and CS provided a higher DM degradation. CS provided a higher NDF degradation rate. OUB provided a lower ruminal pH. Depending on the collection time, the lowest pH value was estimated at 3.79 h after the morning feeding. There was an interaction between treatments and collection time on VFA concentrations. Due to the high degradation rate, greater energy intake, less change in rumen pH, greater volatile fatty acid production, and feasibility, we recommend using cactus associated with sugarcane bagasse plus urea in sheep diets.

The aim of this study was to evaluate the effect of replacing Tifton-85 hay (Cynodon spp. cv. Tifton 85) with 0, 150, 300, 450 and 600 g/kg dry matter (DM) of spineless cactus (SC, Nopalea cochenilifera Salm-Dyck) plus urea and ammonium sulfate (UAS; 9:1) on DM, digestible organic matter (DOM) and indigestible neutral detergent fiber (iNDF) intakes, as well as ruminal fermentation, N-balance, and microbial protein supply (MPS). Five rumen-fistulated and cannulated crossbred wethers, weighing 43.8 ± 5.80 kg, were randomized in a 5 × 5 Latin square design. Isonitrogenous diets (14% crude protein) were supplied with a roughage/concentrate ratio of 70:30. The DOM intake, N-retained, and MPS showed quadratic responses (p < 0.05), with maximum values estimated at the levels of SC+UAS of 414, 438 and 418 g/kg DM, respectively. Rumen pH and ammonia nitrogen, iNDF intake, N-urinary excretion, and serum urea and plasma ammonia reduced linearly (p < 0.05) with increasing SC+UAS inclusion. Ruminal acetate and propionate concentrations increased linearly with increasing SC+UAS inclusion. In wethers fed diets with a roughage/concentrate ratio of 70:30, roughage constituted of a SC+UAS/hay (Tifton-85) ratio of 41:29 is recommended in order to maximize the DOM intake, N-retention, and MPS.

This study aimed to evaluate the effects of replacing earless corn silage (ECS) with cactus cladodes (CC; Opuntia spp.) and sugarcane bagasse (SB) on nutrient intake, digestibility, feeding behavior, milk yield (MY), and composition of lactating dairy cows. Ten Holstein cows, weighing 571 ± 97.0 kg and producing 23.0 ± 4.4 kg of milk per day, were assigned to two contemporaneous 5 × 5 Latin squares. Treatments consisted of five levels of ECS replacement with CC plus SB (0, 25, 50, 75, and 100%). The results showed a linear increase in dry matter (DM) intake (p < 0.05) (15.98 and 18.73 kg/day) and a quadratic increase (p < 0.05) in crude protein and energy intake (2.97 kg/day and 27.52 Mcal/day at 95.4 and 88.6% substitution, respectively). Apparent DM digestibility increased (p < 0.05), but fiber digestibility decreased linearly (p < 0.05). Treatments had a quadratic effect (p < 0.05) on MY and fat-corrected MY (24.17 kg/day and 21.9 kg/day at 63.9% and 38.6% CC plus SB, respectively). Milk fat (3.26 and 2.35%) and total solids content decreased linearly (p < 0.05), whereas the percentages of protein, lactose, and nonfat solids increased (p < 0.05). Additionally, the CC–SB diets linearly reduced the time spent on feeding and rumination and total chewing time. For Holstein cows fed common semiarid diets, milk production can be maximized by replacing 38.6% of ECS with CC plus SB.

The present study explored the combined effects of CC (Opuntia stricta [Haw.] Haw.) and full-fat corn germ (FFCG) as a source of supplementary PUFA on milk fatty acid (FA) composition of dairy goats fed elephant grass (EG). Twelve Saanen goats were used in a replicated 4 × 4 Latin square design in a 2 × 2 factorial arrangement of treatments (GC or FFCG as energy sources, and the inclusion or not of CC in the diet as a partial substitute for EG). The proportions of various milk FAs were influenced by CC, FFCG, or both. Significant interactions between CC and FFCG were noted for most trans-C18:1 and CLA isomers. Specifically, including CC in the FFCG-supplemented diet increased the levels of trans-11 C18:1 and cis-9, trans-11 CLA in milk fat, whereas these isomers were unchanged or slightly reduced with CC in the GC diet. Similar patterns were observed for C18:2 n-6, while C16:0 increased with CC in the GC diet. Ratios of trans-C18:1/C18:0 and trans-11 C18:1/C18:0 were notably higher when CC was included in the FFCG-supplemented diet. These findings suggest that CC inhibits the last step of rumen biohydrogenation in dairy goats, enriching milk with trans-11 C18:1 and cis-9, trans-11 CLA when supplementary PUFA is provided in the diet.